Ubuntu – the difference between appindicator and AppIndicator3

It's the indicator applet's default to group application and system indicators separately, and place application indicators to the left of system indicators, so you'd probably need a modified host applet to do that.

See the specification for further information, and you can also ask for help in #ayatana on Freenode.

Yes, we realize that we need Python documentation with the appropriate level of detail. That is the goal of the Giraffe project. It will work with the GObject Introspection bindings which is the way that new Python applications should be written to use the application indicators.

Until then, the best bet is the API documentation that you've noted. It should be roughly the same though "python-ified".

The build_menu_from_desktop is a convenience function use load the entries that would otherwise be in something like a quicklist in Unity. So to get those entries you'd use build_menu_from_desktop("/my/path/myfile.desktop", "Unity") to specify the TargetEnvironment.

This allows you to have different entries in the desktop file and have some overlap and others not.